Did you get a criminal conviction? No?
Ill answer my question for you! No you don't have a conviction for a simple misdemeanor.
I have a few (4) drug charges to my name, but no criminal convictions. My next offence would have given me a conviction but.

Stupid Australian goverment scaring people into thinking these stupid things.

Just get a letter from a PD department in a town/city you haven't been arrested in. As long as it's not hookedup o like a livescan or something that tracks your identiy you'll be fine.
So lets say you've been arrested but not charged in Irvine california, you can just goto Long beach california to get the letter made.